Systems and methods to effect movement of tissue structures

ABSTRACT

The present disclosure relates generally to medical devices and procedures for placement of a medical device between adjacent tissue structures. In particular, the present disclosure relates to endoscopic systems and methods for preventing or minimizing movement between tissue walls to facilitate placement of a stent therebetween.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of Ser. No. 15/935,969, filed Mar.26, 2018, and claims the benefit of priority under 35 U.S.C. § 119 toU.S. Provisional Patent Application Ser. No. 62/476,995, filed on Mar.27, 2017, which is incorporated by reference in its entirety for allpurposes.

FIELD

The present disclosure relates generally to the field of devices andprocedures for placement of a medical device between adjacent tissuestructures. In particular, the present disclosure relates to endoscopicsystems and methods for preventing or minimizing movement between tissuewalls to facilitate placement of a stent therebetween.

BACKGROUND

Although endoscopic imaging modalities, such as fluoroscopy andendoscopic ultrasound (EUS), allow visualization of anatomicalstructures beyond the tissue directly in front of the endoscope, theinability to control (e.g., stabilize, immobilize, anchor, etc.) thesedistal anatomical structures during an endoscopy procedure presentschallenges. For example, medical procedures such as gastrojejunostomy,hepaticogastrostomy, and gallbladder drainage, require the placement ofa conduit (e.g., stent, etc.) within the appropriate portions ofproximal and distal tissue walls. The tendency to lose control of thedistal tissue wall during transmural stent deployment procedurespresents a significant technical challenge to medical professionals,especially when a direct visual image of the distal tissue wall isunavailable. Failure to properly position the fluid conduit within theappropriate portions of the tissue walls may lead to serious medicalcomplications.

A variety of advantageous medical outcomes may be realized by thesystems and/or methods of the present disclosure, which minimize orprevent proximal and distal tissue walls from moving away from eachother during a transmural stent placement procedure.

SUMMARY

In one aspect, the present disclosure relates to a system comprising aneedle that includes a proximal end, a sharpened distal end, and a lumenextending therebetween. An elongate member may be slidably disposedwithin the lumen, with a distal portion of the elongate memberconfigured to move between a first configuration when disposed withinthe lumen, and a second configuration when disposed distally beyond thesharpened distal end. The distal portion of the elongate member may besubstantially linear in the first configuration, and substantiallynon-linear in the second configuration. The second configuration mayinclude a loop, spiral or figure-eight shape. The distal portion may besplit along a longitudinal axis of the elongate member to define firstand second splines. The first and second splines may be substantiallyco-linear with the elongate member in the first configuration. The firstand second splines may form Y-shape, T-shape or W-shape in the secondconfiguration. Alternatively, the first and second splines formsubstantially spherical or oblong structures in the secondconfiguration.

In another aspect, the present disclosure relates to a system comprisinga needle that includes a proximal end, a sharpened distal end, and alumen extending therebetween. An elongate member may be slidablydisposed within the lumen. The elongate member may include a controlrod, and a sheath slidably disposed around the control rod, with adistal portion of the elongate member configured to move between a firstconfiguration when disposed within the lumen, and a second configurationwhen disposed distally beyond the sharpened distal end. A distal portionof the sheath may include at least one slit formed therein, wherein adistal end of the control rod is attached to a distal end of the sheath.The distal portion of the sheath may move from the second configurationto the first configuration by distally advancing the sheath over thecontrol rod. Alternatively, the distal portion of the sheath may movefrom the first configuration to the second configuration by proximallyretracting the control rod through the sheath. Alternatively, the distalportion of the sheath may move from the first configuration to thesecond configuration by distally advancing the sheath over the controlrod. The distal portion of the sheath may move from the secondconfiguration to the first configuration by distally advancing thecontrol rod through the sheath. Alternatively, the distal portion of thesheath may move from the second configuration to the first configurationby distally retracting the sheath over the control rod. The distalportion of the sheath may form a basket in the second configuration.

In another aspect, the present disclosure relates to a method comprisingadvancing a penetrating a needle with a sharpened distal end and lumenrunning from a proximal end to the distal end through a tissue wall of afirst body lumen and a tissue wall of a second body lumen adjacent tothe first body lumen, and distally advancing an elongate member throughthe lumen of the needle such that the distal portion of the elongatemember moves to a second configuration in contact with a portion of thetissue wall of the second body lumen to effect the position of thesecond body lumen relative to the first body lumen. The method mayfurther include withdrawing the needle from over the elongate member andadvancing a stent delivery system over the elongate member such that adistal end of the stent delivery system forms opposing holes in thetissue walls of the first and second body lumens. The method may furtherinclude deploying a stent from the stent delivery systems between thefirst and second body lumens. The method may further include distallyretracting the elongate member through the stent delivery system andremoving the stent delivery system.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present disclosure are described by wayof example with reference to the accompanying figures, which areschematic and not intended to be drawn to scale. In the figures, eachidentical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment shown where illustration is not necessary to allow those ofordinary skill in the art to understand the disclosure. In the figures:

FIGS. 1A-1G provide perspective views of a system in a delivery (FIG.1A) and deployed (FIGS. 1B-1G) configurations, according to embodimentsof the present disclosure.

FIGS. 2A-2E provide perspective views of a system in a delivery (FIG.2A) and deployed (FIGS. 2B-2E) configurations, according to embodimentsof the present disclosure.

FIGS. 3A-3C provide perspective views of a system in a delivery (FIGS.3A-3B) and deployed (FIG. 3C) configuration, according to one embodimentof the present disclosure.

FIGS. 4A-4F provide perspective views of a stent deployment procedureusing a system, according to one embodiment of the present disclosure.

FIGS. 5A-5C provide perspective views of a stent deployment using thesystem of FIG. 2E, according to one embodiment of the presentdisclosure.

DETAILED DESCRIPTION

The present disclosure is not limited to the particular embodimentsdescribed. The terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting beyondthe scope of the appended claims. Unless otherwise defined, alltechnical terms used herein have the same meaning as commonly understoodby one of ordinary skill in the art to which the disclosure belongs.

Although embodiments of the present disclosure are described withspecific reference to certain procedures, such as a gastrojejunostomyprocedure, the systems and methods described herein may be used toposition a fluid conduit between a variety of adjacent tissue walls,organs, vessels and/or body lumens.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” or “includes” and/or “including” when used herein,specify the presence of stated features, regions, steps elements and/orcomponents, but do not preclude the presence or addition of one or moreother features, regions, integers, steps, operations, elements,components and/or groups thereof.

As used herein, the term “distal” refers to the end farthest away fromthe medical professional when introducing a device into a patient, whilethe term “proximal” refers to the end closest to the medicalprofessional when introducing a device into a patient.

In various of the embodiments described here and in other embodiments,the present disclosure relates to a system which prevents or minimizesmovement between tissue walls during a transmural medical procedure inwhich a direct visual image and/or control of the distal tissue wall isdifficult or not available.

Referring to FIG. 1A, in one embodiment, a system 100 of the presentdisclosure may include a tissue-penetrating element 110 (e.g., needle,etc.) comprising a proximal end (not shown), a sharpened distal end 114and a lumen 116 extending therebetween. An elongate member 120 (e.g.,rail, guidewire, etc.) comprising a proximal end (not shown) and adistal end 124 may be slidably disposed within the lumen 116 of thetissue-penetrating element 110. A distal portion 125 of the elongatemember 120 may be split (e.g., divided) along a longitudinal axisthereof to define first and second splines 125 a, 125 b (e.g., tines,forks, branches, prongs, arms, etc.). The first and second splines 125a, 125 b may be substantially co-linear with a longitudinal axis of theelongate member 120 when disposed within the lumen 116 of the tissuepenetrating element 110. At least the distal portion 125 of the elongatemember 120 may include a variety of shape memory materials as are knownin the art (e.g., metals, alloys, polymers, and the like), configured tomove between a first configuration when disposed within lumen 116 of thetissue-penetrating element 110, and a second configuration when disposeddistally beyond the sharpened distal end 114 of the tissue-penetratingelement 110. The distal portion 125 of the elongate member 120 is notlimited to two splines, but may include any number of splines (e.g.,three or more splines).

Referring to FIG. 1B, in one embodiment, the first and second splines125 a, 125 b may move or deflect substantially perpendicular to thelongitudinal axis of the elongate member 120 to form a “T-shape” when inthe second configuration. Referring to FIG. 1C, in one embodiment, thefirst and second splines 125 a, 125 b may move or deflect substantiallytangential to the longitudinal axis of the elongate member 120 to form a“Y-shape” when in the second configuration. Referring to FIG. 1D, in oneembodiment, the first and second splines 125 a, 125 b may bend backalong/over and parallel to the longitudinal axis of the elongate member120 to form a “W-shape” when in the second configuration. Referring toFIG. 1E, in one embodiment, the first and second splines 125 a, 125 bmay curl back along/over the longitudinal axis of the elongate member120 to form opposed substantially spherical (e.g., circular) shapes whenin the second configuration. Referring to FIG. 1F, in one embodiment,the first and second splines 125 a, 125 b may curl back along/over thelongitudinal axis of the elongate member 120 to form opposedsubstantially oblong (e.g., elliptical, elongate sphere, etc.) shapeswhen in the second configuration. Referring to FIG. 1G, in oneembodiment, the first and second splines 125 a, 125 b may curl backalong/over the longitudinal axis of the elongate member to form opposedsubstantially oblong shapes, which are spaced apart (e.g., separated)from the longitudinal axis of the elongate member when in the secondconfiguration. Although the distal portions 125 of the elongate members120 are depicted as forming substantially symmetrical structures, invarious embodiments the first and second splines 125 a, 125 b may formany combination of the second configurations depicted in FIGS. 1B-1G, orother configurations not depicted. In various embodiments, when in thesecond configuration, the first and second splines 125 a, 125 b may move(e.g., deflect, bend, twist, compress, etc.) independent of each otherwhen placed in contact with an inner surface of a tissue wall, asdiscussed below.

Referring to FIG. 2A, in one embodiment, a system 200 of the presentdisclosure may include a tissue-penetrating element 210 (e.g., needle,etc.) comprising a proximal end (not shown), a sharpened distal end 214and a lumen 216 extending therebetween. An elongate member 220 (e.g.,rail, guidewire, etc.) comprising a proximal end (not shown) and adistal end 224 may be slidably disposed within the lumen 216 of thetissue-penetrating element 210. At least the distal portion 225 of theelongate member 220 may include a variety of shape memory materials asare known in the art (e.g., metals, alloys, polymers, and the like),configured to move between a first configuration when disposed withinlumen 216 of the tissue-penetrating element 210, and a secondconfiguration when disposed (advanced) distally beyond the sharpeneddistal end 214 of the tissue-penetrating element 210. Referring to FIG.2B, in one embodiment, the distal portion 225 of the elongate member 220may form a “loop” or “hoop” when in the second configuration. Referringto FIG. 2C, in one embodiment, the distal portion 225 of the elongatemember 220 may bend approximately 180 degrees relative to thelongitudinal axis of the elongate member 220 to form a “reverse coil” or“reverse spiral” around a portion of the elongate member 220 when in thesecond configuration. Referring to FIG. 2D, in one embodiment, thedistal portion 225 of the elongate member 220 may form a “figure-eight,”lasso,” or “cork screw” shape when in the second configuration.Referring to FIG. 2E, in one embodiment, the distal portion 225 of theelongate member 220 may bend to form a “cross-bar” that extends acrossthe longitudinal axis of the elongate member 220 when in the secondconfiguration.

The various second configurations of the distal portions 125, 225 mayprovide a number of additional benefits to further secure/immobilize thedistal tissue wall when the elongate member 120, 220 is proximallyretracted. By way of non-limiting example, the ends of the first andsecond prongs 125 a, 125 b depicted in any of FIGS. 1B-1D may partiallypenetrate/embed within the distal tissue wall. A portion of the splines125 a, 125 b in any of FIGS. 1B-1G, or the distal portion 225 of theelongate member 220 of FIGS. 2B-2E, may include one or more hooks,barbs, prongs, etc. to provide enhanced friction against an inner wallof the distal tissue. In various embodiments, the splines 125 a, 125 band/or distal portion 225 of the elongate member 220 may provide agradual increase in retention pressure when the elongate member 120, 220is proximally retracted, thereby allowing the medical professional toexert more or less immobilizing force against the inner surface of thedistal tissue wall as necessary throughout the course of the medicalprocedure. In addition, or alternatively, a portion of the surface ofthe splines 125 a, 125 b of any of FIGS. 1B-1D may include a sharpenededge configured to enlarge or expand the puncture hole created by thesharpened distal end 114 of the tissue-penetrating element 110 withinthe first and/or second tissue walls. One, or both, of the spherical oroblong shapes of FIGS. 1E-1G, respectively, may deflect (e.g., bend,splay, etc.) away from the longitudinal axis of the elongate member 120to provide retention pressure across a larger surface area of the distaltissue.

Referring to FIGS. 3A-3C, in one embodiment, a system 300 of the presentdisclosure may include a tissue-penetrating element 310 (e.g., needle,etc.) comprising a proximal end (not shown), a sharpened distal end 314and a lumen 316 extending therebetween. An elongate member 320 may beslidably disposed within the lumen 316 of the tissue-penetrating element310. The elongate member 320 may include a control rod 322 slidablydisposed within a sheath 326. A distal end 324 of the control rod 322may be attached to a distal end 327 of the sheath 326. A distal portion325 of the sheath 326 may include one or more slits 329 formed therein,and be configured to move between a first configuration when disposedwithin lumen 316 of the tissue-penetrating element 310 (FIG. 3A), and asecond configuration when disposed distally beyond the sharpened distalend 314 of the tissue-penetrating element 310 (FIG. 3C).

For example, at least the distal portion 325 of the sheath 326 mayinclude a variety of materials, including, but not limited to shapememory materials, e.g., nitinol, polyether ether ketone (PEEK), etc.,into which the one or more slits 329 are formed using, e.g., lasercutting. The elongate member 320 may be advanced through the lumen 316of the tissue-penetrating element 320 by distally advancing the controlrod 322 (FIG. 3B). In one embodiment, the distal portion 325 of thesheath 326 may move to the second configuration by distally advancingthe sheath 326 over/along the control rod 322. Alternatively, the distalportion 325 of the sheath 326 may move to the second configuration byproximally retracting the control rod 322 through/within the sheath 326(FIG. 3C). In either embodiment, the one or more slits 329 may allow thedistal portion 325 to form a “basket” that includes a series of arms orpetals configured to engage the distal tissue wall. In one embodiment,the distal portion 325 may include one or more hooks, barbs, prongs,etc. for enhanced friction against the distal tissue wall. AlthoughFIGS. 3A-3C depict an embodiment in which the distal portion 325includes 5 slits configured to form 5 arms or petals when in the secondconfiguration, in various embodiments, the distal portion may includeany number of slits configured to form a variety of secondconfigurations.

In one embodiment, the elongate members 120, 220, 320 disclosed hereinmay be disposed within, and delivered through, a tissue-penetratingelement 110, 210, 310 that includes a 19 or 21-gauge needle used forfine-needle aspiration (FNA) or fine-needle biopsy (FNB) procedures, asare known in the art. In addition, or alternatively, the tissuepenetrating elements 110, 210, 310 and/or elongate members 120, 220, 320may beneficially include a coating, such as a fluorinated polymer orparalene, to provide electrical insulation and/or improved lubricity. Toprevent coring of the proximal or distal tissue walls, the distalportion 125, 225, 325 of the elongate member 120, 220, 320 may beconfigured to obturate the lumen 116, 216, 316 at or near the sharpeneddistal end 114, 214, 314 of the tissue-penetrating element 110, 210,310.

In one embodiment, a system 100, 200, 300 of the present disclosure maybe delivered through the working channel of an endoscope. Referring toFIG. 4A, in use and by way of example, an ultrasound endoscope 130 maybe advanced through the esophagus into a first body lumen 140 (e.g., thestomach). The distal end 132 of the endoscope 130 may include a camera137, light source 138 and ultrasound transducer 139. Using the directview (e.g., the light source 138 and camera 137) the distal end 132 ofthe endoscope 130 may be positioned adjacent to a tissue wall 142 (e.g.,proximal tissue wall) of the first body lumen 140 which is in thevicinity of the tissue wall 152 (e.g., distal tissue wall) of a secondbody lumen 150 (e.g., the duodenum or jejunum). The second body lumen150 may then be imaged through the first tissue wall 142 by switchingthe endoscope 130 from the direct view to an ultrasound view (e.g.,turning off the light source 138 and turning on the ultrasoundtransducer 139). The system 100 may then be advanced through the workingchannel 136 of the endoscope 130 such that the sharpened distal end 114of the tissue-penetrating element 110 penetrates the first and secondtissue walls 142, 152, and extends into the second body lumen 150.

Referring to FIG. 4B, the elongate member 120 may be distally advancedbeyond the sharpened distal end of the tissue-penetrating element suchthat the distal portion 125 moves to the second configuration within thesecond body lumen 150. The tissue-penetrating element may then beremoved along/over the elongate member 120 (e.g., proximally withdrawn)through the working channel 136 of the endoscope 130. The elongatemember 120 may then be proximally retracted to place the distal portion125 in contact with an inner portion of the second distal tissue wall152, and with sufficient force to minimize or prevent (e.g., anchor)movement of the distal tissue wall 162 relative to the proximal tissuewall 152.

Referring to FIG. 4C, with the proximal and distal tissue walls 142, 152sufficiently immobilized with respect to each other, a stent deliverysystem 160 with a stent 162 loaded thereon may be advanced through theworking channel 136 of the endoscope 130. The stent delivery system 160may include a lumen 166 configured to slide over/along the elongatemember 120. The distal end of the stent delivery system 160 may includea cutting element, e.g., electrocautery surface, configured to createopposed openings (e.g., holes) through the first and second tissue walls142, 152. In one embodiment, the distal portion 125 of the elongatemember 120 may provide a firm/secure platform against which theelectrocautery surface of the stent delivery system 160 may press whenforming the opposed openings. The distal portion 125 may provide theadditional benefit of establishing separation between the oppositetissue wall of the second body lumen 150 and the stent delivery systemto prevent unintentional cutting by the cutting element. In oneembodiment, one (or both) of the oblong portions of the distal portion125 may deflect away from the longitudinal axis of the elongate member120 to provide retention pressure across a larger surface area of thedistal tissue wall. In addition, or alternatively, the ability of thedistal portion(s) 125 to deflect away from the longitudinal axis of theelongate member 120 may provide a space to allow: 1) the cutting elementof the delivery system 160 to fully penetrate the second body lumen 150,2) unhindered deployment of the distal flange 166 of stent 162 (FIG.4D), and/or 3) introduction of an additional cutting element to furtherdilate (e.g., enlarge) the tissue opening without imparting excessiveforce on the opposite tissue wall of the second body lumen 150. Inaddition, the oblong shape may provide a degree of flexibility to thedistal portion 125, such that the stent delivery system 160 may beadvanced a sufficient distance into the second body lumen 150 to deploythe distal flange without further pushing the distal portion 125 againstthe opposite tissue wall. The distal portion 125 of the elongate member120 may include a soft and/or compliant surface or coating to preventtrauma to the opposite tissue wall in the event contact therebetweenoccurs.

Referring to FIG. 4D, an outer portion of the stent delivery system 160may then be proximally retracted over the inner lumen 166, elongatemember 120 and stent 162 to deploy the distal flange 165 of a stent 162within the second body lumen 150. Referring to FIG. 4E, the outerportion of the stent delivery system 160 may be further retracted overthe inner lumen 166, the elongate member 120 and the stent 162 to deploythe proximal flange 164 of the stent 162 within the first body lumen140. Referring to FIG. 4F, with the proximal and distal flanges 164, 165properly deployed within the first and second body lumens 140, 150, theelongate member 120 may be proximally retracted with sufficient forcesuch that the distal portion 125 moves from the second configuration tothe first configuration for removal through the lumen 166 of the stentdelivery system. The endoscope 130, stent delivery system 160 andelongate member 120 may then be removed from the patient. The stentconfiguration depicted in FIGS. 4D-4F is provided by way of non-limitingexample, and may include a variety of different shapes, configurations,orientations, dimensions and/or materials as required to provide a flowpathway between adjacent tissue walls. In addition, an outer and/orinner surface of the stent may be fully or partially covered (e.g.,across the saddle region between the proximal and distal flanges) toprevent fluid leakage between the tissue walls. Although FIGS. 4E-4Fdepict a gap between the tissue walls of the first and second bodylumens 140, 150 after placement of the stent, in other embodiments theprocedure may result in the tissue walls being apposed into contact witheach other along the saddle region, with the proximal and distal flangesproviding contact with the respective inner surface of each tissue wall.

Although the systems 100, 200, 300 disclosed herein are configured tominimize or prevent proximal and distal tissue walls from moving awayfrom each other during a medical procedure, rather than moving eithertissue wall towards the other, in one embodiment, the elongate member120, 220, 320 may be proximally retracted with sufficient force suchthat the distal portion 125, 225, 325 pulls the distal tissue wall overthe stent delivery system 160 for deployment of the distal flange withinthe second body lumen 150.

Referring to FIGS. 5A-5C, in one embodiment, the distal portion 225 ofthe elongate member 220 of FIG. 2E may include a first dimension D₁(e.g., a width), a second dimension D₂ (e.g., a height) and a thirddimension D₃ (e.g., an elevation) relative to the longitudinal axis ofthe elongate member 220. By way of non-limiting example, the firstdimension D₁ may be approximately 1.00 inches, the second dimension D₂may be approximately 0.78 inches and the third dimension D₃ may beapproximately 0.33 inches. In various embodiments, the first, second andthird dimensions D₁-D₃ of the distal portion 225 may provide a spacewithin which the distal flange 165 of a stent 162 may be deployed (e.g.,within a second body lumen, as outlined above), while the distal portion225 of the elongate member maintains contact with the tissue wall of thesecond body lumen throughout the stent deployment procedure.

In various embodiments, the elongate members 120, 220, 320 disclosedherein may be include sufficient flexibility and strength to repeatedlyslide into and out of a tissue-penetrating element, or other medicaldevice (e.g., retraction catheter, etc.), without breaking/fracturingand while maintaining the ability to move to the second configurationwithin the second body lumen (e.g., to provide the requisite retentionstrength). In addition, any of the elongate members 120, 220, 320disclosed herein may include a suitable coating to facilitate slidablemotion within a tissue-penetrating element, or other medical device. Invarious embodiments, such coating(s) may also impart dielectric strengththe all, or a portion of, the elongate member.

The medical devices of the present disclosure are not limited toendoscopes, and may include a variety of medical devices for accessingbody passageways, including, for example, catheters, bronchoscopes,ureteroscopes, duodenoscopes, colonoscopes, arthroscopes, cystoscopes,hysteroscopes, and the like. Finally, although the embodiments of thepresent disclosure have been described in use with an endoscope, thesystems of the present disclosure may be positioned within the patientin the absence of an accompanying medical device.

All of the devices and/or methods disclosed and claimed herein can bemade and executed without undue experimentation in light of the presentdisclosure. While the devices and methods of this disclosure have beendescribed in terms of preferred embodiments, it may be apparent to thoseof skill in the art that variations can be applied to the devices and/ormethods and in the steps or in the sequence of steps of the methoddescribed herein without departing from the concept, spirit and scope ofthe disclosure. All such similar substitutes and modifications apparentto those skilled in the art are deemed to be within the spirit, scopeand concept of the disclosure as defined by the appended claims.

What is claimed is:
 1. An elongate member slidable longitudinallythrough a lumen and transversely through a proximal wall of a bodylumen, said elongate member comprising: a distal end having a distalportion configured to move between a first configuration when disposedwithin the lumen, and a second expanded configuration when disposeddistally beyond the distal end of the lumen and distally through thebody lumen proximal wall; wherein in the second configuration, saiddistal portion of said elongate member is dimensioned to extendtransverse to an axis of the body lumen to create a space in the bodylumen between the proximal wall of the body lumen and a distal wall ofthe body lumen, said distal portion of said elongate member beingpositioned within the space to shield the distal wall of the body lumenfrom a further instrument entering the body lumen through the proximalwall of the body lumen.
 2. The system of claim 1, further comprising atissue-penetrating element having a sharpened distal end configured topenetrate the proximal wall of the body lumen, and a lumen definedtherethrough, said elongate member extending through the lumen of saidtissue-penetrating element.
 3. The system of claim 1, further comprisinga cutting element, wherein said distal portion of said elongate memberin the second configuration is dimensioned to create a space to allowsaid cutting element to extend into the body lumen through a proximalwall of the body lumen without cutting or imparting excessive force onthe distal wall of the body lumen opposite the proximal wall.
 4. Thesystem of claim 1, further comprising a cutting element, said distalportion of said elongate member in the second configuration provides aplatform within the body lumen against which said cutting element maypress when cutting through the proximal tissue wall of the body lumen.5. The system of claim 1, further comprising a stent, wherein saiddistal portion of said elongate member is dimensioned to create a spacefor expansion of at least a portion of said stent within the body lumen.6. The system of claim 5, wherein said stent has a distal flange, andsaid distal portion of said elongate member is dimensioned to create aspace for unhindered deployment of said distal flange of said stent. 7.The system of claim 5, further comprising a stent delivery systemincluding a cutting element, wherein said distal portion of saidelongate member is dimensioned to create a space to allow said cuttingelement to extend into the body lumen through a proximal wall of thebody lumen without cutting the distal wall of the body lumen oppositethe proximal wall.
 8. The system of claim 7, wherein said distal portionof said elongate member is dimensioned to maintain contact with the bodylumen during deployment of said stent.
 9. A system comprising: anelongate member; and a stent wherein: said elongate member has a distalend with a distal portion configured to move between a firstconfiguration when disposed within a lumen, and a second configurationwhen disposed distally beyond the distal end of the lumen andtransversely across a body lumen; and in the second configuration, saiddistal portion of said elongate member provides space for deployment ofat least a portion of said stent within the body lumen.
 10. The systemof claim 9, further comprising a stent delivery system including acutting element, wherein said distal portion of said elongate member isdimensioned to create a space to allow said cutting element to extendinto the body lumen through a proximal wall of the body lumen withoutcutting the distal wall of the body lumen opposite the proximal wall ofthe body lumen.
 11. The system of claim 9, further comprising a stentdelivery system including a cutting element, said distal portion of saidelongate member providing a platform against which said cutting elementof said stent delivery system may press.
 12. The system of claim 11,wherein said distal portion of said elongate member provides a spacebetween a proximal wall of the body lumen and a distal wall of the bodylumen opposite the body lumen proximal wall to prevent unintentionalcutting of the body lumen distal wall by said cutting element.
 13. Thesystem of claim 9, wherein said distal portion of said elongate memberprovides a space between a proximal wall of the body lumen and a distalwall of the body lumen opposite the body lumen proximal wall to shieldthe body lumen distal wall from a further instrument entering the bodylumen through the body lumen proximal wall.
 14. An elongate memberslidable longitudinally through a lumen and transversely through aproximal tissue wall and through a proximal wall of a body lumen, saidelongate member comprising: a distal end having a distal portionconfigured to move between a first configuration when disposed withinthe lumen, and a second expanded configuration when disposed distallybeyond the distal end of the lumen and beyond the body lumen proximalwall; wherein in the second configuration, said distal portion of saidelongate member is configured to minimize movement of the body lumenproximal wall relative to the proximal tissue wall.
 15. The elongatemember of claim 14, further comprising a tissue-penetrating elementhaving a sharpened distal end configured to penetrate the body lumenproximal wall, and a lumen defined therethrough, said elongate memberextending through the lumen of said tissue-penetrating element.
 16. Thesystem of claim 14, wherein in the second configuration said distalportion of said elongate member is configured to increase retentionpressure across a surface of the body lumen proximal wall.
 17. Thesystem of claim 16, wherein in the second configuration said distalportion of said elongate member is configured to gradually increaseretention pressure when said elongate member is retracted proximally.18. The system of claim 14, wherein said distal portion of said elongatemember is configured to enhance friction against the body lumen proximalwall.
 19. The system of claim 14, further comprising a stent deliverysystem including a stent and a cutting element, wherein in the secondconfiguration said distal portion of said elongate member minimizesmovement of the body lumen proximal wall relative to the proximal tissuewall to facilitate advancement of said cutting element and said stentthrough the body lumen proximal wall.
 20. The system of claim 19,wherein in the second configuration said distal portion of said elongatemember provides a space between the body lumen proximal wall and thedistal wall of the body lumen opposite the body lumen proximal wall toprevent unintentional cutting of the body lumen distal wall by saidcutting element.